Pokemon.js

class Pokemon {
  constructor(name, attack, defense, health, type) {
    this.name = name;
    this.attack = attack;
    this.defense = defense;
    this.health = health;
    this.type = type;

    this.initialHealth = health;
  }

  takeDamage(amount) {
    this.health = Math.max(this.health - amount, 0);
  }

  attackOpponent(Opponent) {
    const damage = Math.max(this.attack - Opponent.defense, 1);
    Opponent.takeDamage(damage);
  }

  display() {
    const { name, type, health, initialHealth } = this;
    return `${name.toUpperCase()} (${type.toUpperCase()}) ${health}/${initialHealth}`;
  }
}

module.exports = Pokemon;